1. Field of the Invention
The present invention relates to a method for recording and reproducing coded signals of a motion picture (video signal) and a sound (audio signal), and an apparatus for recording and reproducing the coded signals transmitted from a transmission system to and from a recording medium, and particularly, relates to a recording and reproducing apparatus capable of performing a decoded reproduction in real-time processing while the coded signal transmitted from the transmission system is recorded in the recording medium.
2. Description of the Related Art
Presently, as to an apparatus for recording and reproducing a coded signal transmitted from a transmission system, there is proposed a method for reproducing in real time the coded signal which has been transmitted for a time shorter than an actual reproduction time of a program, for instance, a 2-hour reproduction time and is recorded in a recording medium by making use of a transmission system capable of transmitting the coded signal at a transmission rate higher than a coding rate.
In the method in the prior art mentioned above, the transmission time of the data depends on an actual reproduction time and the transmission rate of the program.
Exemplarily, when a 2-hour program having the transmission rate of 4 Mbps is intended to be transmitted for 10 minutes, it requires a transmission band of 48 Mbps which is 12 times as large as that of 4 Mbps.
FIG. 1 is a chart showing a time relation between the transmission time of data of a program and a reproduction time of the data thereof in the prior art.
As seen from FIG. 1, after the start of the data transmission (TMS) of a program, it takes 10 minutes to transmit all the data of a program. It should be noted that the data trasmitted are instantly recorded in the recording medium. Thus, there is needed a waiting time of 10 minutes before the reproduction of the program.
In order to obtain an enough performance, it requires a rather large transmission band width. On the contrary, when the transmission band width are limited, it requires a long transmission time. This poses problems of the long waiting time and degradation of image and sound quality due to the suppression of the transmission rate.